Introduction Melanoma, responsible for most skin cancer deaths globally, has mortality rates expected to double by 2040. Pembrolizumab is a highly selective antibody approved for melanoma treatment and other cancers. Despite new treatments for melanoma, high treatment costs and long approval times limit patient access to new therapies. To support decision-making regarding metastatic melanoma therapies, a model was developed to calculate the number needed to treat (NNT) and the cost of preventing an event (COPE) using KEYNOTE-716 (NCT03553836) data.